1. Field of the Invention
The present invention relates to a 3-dimensional image expression method and apparatus, and more particularly, to a 3-dimensional image expression method and apparatus for defining virtual reality modeling language (VRML) nodes and fields and synthesizing and expressing multiple effects and multiple textures in a 3-dimensional image by using the defined VRML nodes and fields.
2. Description of Related Art
A virtual reality modeling language (VRML) is a standard language for expressing a 3-dimensional graphic image in the Internet. In order to express the 3-dimensional graphic image by using the VRML, there is a need to define nodes as basic elements constituting VRML objects and specific values constituting each of the nodes and fields designating the nodes.
A VRML standard defines the basic nodes. A user may define new nodes as prototypes in order to extend nodes in addition to the defined basic nodes.
FIG. 1 shows a structure of nodes basically defined in accordance with the VRML standard. The nodes include Shape, Geometry, Appearance TextureCoordinate, Material, TextureTransform, ImageTexture, PixelTexture, and MovieTexture nodes. The Shape is a root node for generating a 3-dimensional object. The Geometry node designates a shape of the 3-dimensional object. The Appearance node designates an appearance of the 3-dimensional object. The TextureCoordinate node designates coordinates of textures expressed in the appearance of the 3-dimensional object. The Material node designates attributes such as colors of the appearance of the 3-dimensional object. The TextureTransform node designates a transform of the textures. The ImageTexture defines a texture map to be expressed on the 3-dimensional object by using a still image. The PixelTexture node defines a texture map to be expressed on the 3-dimensional object by using a point image. The MovieTexture node defines a time-varying texture map by using a moving picture image. The three texture-associated nodes are designated by using texture fields included in the Appearance node. These nodes include fields defined to designate specific values for expressing the 3-dimensional object and other nodes.
Now, a method of expressing the 3-dimensional image based on the defined VRML nodes and fields will be described.
The user writes a VRML file in accordance with the defined nodes and fields in order to express the 3-dimensional image. The user uses a VRML browser to read out the written VRML file. A parser included in the browser analyses the read-out VRML file to identify internal nodes basically defined in the VRML standard and the newly-user-defined prototype nodes. The VRML browser generates a transformation hierarchy and a route graph by using a result of the VRML file analysis. An execution engine included in the VRML browser output an original appearance of the 3-dimensional image on a screen and waits for a user's input. The execution engine processes events defined in the nodes with reference to the generated route graph and outputs the transformed 3-dimensional image on the screen.
In order to express the 3-dimensional graph image, there is a need for a multiple effect expression method and apparatus for synthesizing and expressing user's desired multiple effects or textures in the 3-dimensional image. In addition, since the VRML nodes shown in FIG. 1 support only the simple texture expression, there is a need to define nodes and fields for expressing the multiple effects or textures in the 3-dimensional image by using the VRML, that is, a standard image expression language. In addition, there is a need for a method and apparatus for expressing the effects and textures in the 3-dimensional image by using the defined nodes and fields.